Choosing antibiotics for intra-abdominal infections: what do we mean by "high risk"?

Management of intra-abdominal infections: recommendations by the Italian council for the optimization of antimicrobial use

Intra-abdominal infections (IAIs) are common surgical emergencies and are an important cause of morbidity and mortality in hospital settings, particularly if poorly managed. The cornerstones of effective IAIs management include early diagnosis, adequate source control, appropriate antimicrobial therapy, and early physiologic stabilization using intravenous fluids and vasopressor agents in critically ill patients. Adequate empiric antimicrobial therapy in patients with IAIs is of paramount importance because inappropriate antimicrobial therapy is associated with poor outcomes. Optimizing antimicrobial prescriptions improves treatment effectiveness, increases patients' safety, and minimizes the risk of opportunistic infections (such as Clostridioides difficile) and antimicrobial resistance selection. The growing emergence of multi-drug resistant organisms has caused an impending crisis with alarming implications, especially regarding Gram-negative bacteria. The Multidisciplinary and Intersociety Italian Council for the Optimization of Antimicrobial Use promoted a consensus conference on the antimicrobial management of IAIs, including emergency medicine specialists, radiologists, surgeons, intensivists, infectious disease specialists, clinical pharmacologists, hospital pharmacists, microbiologists and public health specialists. Relevant clinical questions were constructed by the Organizational Committee in order to investigate the topic. The expert panel produced recommendation statements based on the best scientific evidence from PubMed and EMBASE Library and experts' opinions. The statements were planned and graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) hierarchy of evidence. On November 10, 2023, the experts met in Mestre (Italy) to debate the statements. After the approval of the statements, the expert panel met via email and virtual meetings to prepare and revise the definitive document. This document represents the executive summary of the consensus conference and comprises three sections. The first section focuses on the general principles of diagnosis and treatment of IAIs. The second section provides twenty-three evidence-based recommendations for the antimicrobial therapy of IAIs. The third section presents eight clinical diagnostic-therapeutic pathways for the most common IAIs. The document has been endorsed by the Italian Society of Surgery.

Optimized Treatment of Nosocomial Peritonitis

This comprehensive review aims to provide a practical guide for intensivists, focusing on enhancing patient care associated with nosocomial peritonitis (NP). It explores the epidemiology, diagnosis, and management of NP, a significant contributor to the mortality of surgical patients worldwide. NP is, per definition, a hospital-acquired condition and a consequence of gastrointestinal surgery or a complication of other diseases. NP, one of the most prevalent causes of sepsis in surgical Intensive Care Units (ICUs), is often associated with multi-drug resistant (MDR) bacteria and high mortality rates. Early clinical suspicion and the utilization of various diagnostic tools like biomarkers and imaging are of great importance. Microbiology is often complex, with antimicrobial resistance escalating in many parts of the world. Fungal peritonitis and its risk factors, diagnostic hurdles, and effective management approaches are particularly relevant in patients with NP. Contemporary antimicrobial strategies for treating NP are discussed, including drug resistance challenges and empirical antibiotic regimens. The importance of source control in intra-abdominal infection management, including surgical and non-surgical interventions, is also emphasized. A deeper exploration into the role of open abdomen treatment as a potential option for selected patients is proposed, indicating an area for further investigation. This review underscores the need for more research to advance the best treatment strategies for NP.

Korean Guidelines for Use of Antibiotics for Intra-abdominal Infections in Adults

The guidelines are intended to provide practical information for the correct use of antibiotics for intra-abdominal infections in Korea. With the aim of realizing evidence-based treatment, these guidelines for the use of antibiotics were written to help clinicians find answers to key clinical questions that arise in the course of patient care, using the latest research results based on systematic literature review. The guidelines were prepared in consideration of the data on the causative pathogens of intra-abdominal infections in Korea, the antibiotic susceptibility of the causative pathogens, and the antibiotics available in Korea.

A Proposal for a Classification Guiding the Selection of Appropriate Antibiotic Therapy for Intra-Abdominal Infections

Adequately controlling the source of infection and prescribing appropriately antibiotic therapy are the cornerstones of the management of patients with intra-abdominal infections (IAIs). Correctly classifying patients with IAIs is crucial to assessing the severity of their clinical condition and deciding the strategy of the treatment, including a correct empiric antibiotic therapy. Best practices in prescribing antibiotics may impact patient outcomes and the cost of treatment, as well as the risk of “opportunistic” infections such as Clostridioides difficile infection and the development and spread of antimicrobial resistance. This review aims to identify a correct classification of IAIs, guiding clinicians in the selection of the best antibiotic therapy in patients with IAIs.

Microbial Spectrum and Antibiotic Resistance in Patients Suffering from Penetrating Crohn's Disease

Intraabdominal abscess formation occurs in up to 30% of patients suffering from Crohn´s disease (CD). While international guidelines recommend a step-up approach with a combination of empiric antibiotic therapy and percutaneous drainage to delay or even avoid surgery, evidence about microbial spectrum in penetrating ileitis is sparse. We retrospectively assessed outcomes of 46 patients with terminal penetrating Ileitis where microbial diagnostics have been performed and compared microbial spectrum and antibiotic resistance profile of CD patients with patients suffering from diverticulitis with intraabdominal abscess formation. In both groups, the most frequently isolated pathogen was the gram-negative bacterium E. coli belonging to the family of Enterobacterales. However, overall Enterobacterales were significantly more often verifiable in the control group than in CD patients. Furthermore, microbial analysis showed significant differences regarding isolation of anaerobic pathogens with decreased frequency in patients with CD. Subgroup analysis of CD patients to evaluate a potential influence of immunosuppressive therapy on microbial spectrum only revealed that Enterobacterales was less frequently detected in patients treated with steroids. Immunosuppressive therapy did not show any impact on all other groups of pathogens and did not change antibiotic resistance profile of CD patients. In conclusion, we were able to demonstrate that the microbial spectrum of CD patients does differ only for some pathogen species without increased rate of antibiotic resistance. However, the empiric antibiotic therapy for CD-associated intra-abdominal abscess remains challenging since different points such as local epidemiological and microbiological data, individual patient risk factors, severity of infection, and therapy algorithm including non-surgical and surgical therapy options should be considered before therapeutical decisions are made.

Risk Factors for Mortality in Abdominal Infection Patients in ICU: A Retrospective Study From 2011 to 2018

To identify the risk factors related to the patient's 28-day mortality, we retrospectively reviewed the records of patients with intra-abdominal infections admitted to the ICU of Nanfang Hospital, Southern Medical University from 2011 to 2018. Multivariate Cox proportional hazard regression analysis was used to identify independent risk factors for mortality. Four hundred and thirty-one patients with intra-abdominal infections were analyzed in the study. The 28-day mortality stepwise increased with greater severity of disease expression: 3.5% in infected patients without sepsis, 7.6% in septic patients, and 30.9% in patients with septic shock (p < 0.001). In multivariate analysis, independent risk factors for 28-day mortality were underlying chronic diseases (adjusted HR 3.137, 95% CI 1.425–6.906), high Sequential Organ Failure Assessment (SOFA) score (adjusted HR 1.285, 95% CI 1.160–1.424), low hematocrit (adjusted HR 1.099, 95% CI 1.042–1.161), and receiving more fluid within 72 h (adjusted HR 1.028, 95% CI 1.015–1.041). Compared to the first and last 4 years, the early use of antibiotics, the optimization of IAT strategies, and the restriction of positive fluid balance were related to the decline in mortality of IAIs in the later period. Therefore, underlying chronic diseases, high SOFA score, low hematocrit, and receiving more fluid within 72 h after ICU admission were independent risk factors for patients' poor prognosis.

Development and Validation of a Predictive Scoring System for In-hospital Death in Patients With Intra-Abdominal Infection: A Single-Center 10-Year Retrospective Study

Objective: To develop and validate a scoring system to predict the risk of in-hospital death in patients with intra-abdominal infection (IAI).

Materials and Methods: Patients with IAI (n = 417) treated at our hospital between June 2010 and May 2020 were retrospectively reviewed. Risk factors for in-hospital death were identified by logistic regression analysis. The regression coefficients of each risk factor were re-assigned using the mathematical transformation principle to establish a convenient predictive scoring system. The scoring system was internally validated by bootstrapping sample method.

Results: Fifty-three (53/417, 12.7%) patients died during hospitalization. On logistic regression analysis, high APACHE II score (P = 0.012), pneumonia (P = 0.002), abdominal surgery (P = 0.001), hypoproteinemia (P = 0.025), and chronic renal insufficiency (P = 0.001) were independent risk factors for in-hospital death. On receiver operating characteristic curve analysis, the composite index combining these five risk factors showed a 62.3% sensitivity and 80.2% specificity for predicting in-hospital death (area under the curve: 0.778; 95% confidence interval: 0.711–0.845, P < 0.001). The predictive ability of the composite index was better than that of each independent risk factor. A scoring system (0–14 points) was established by re-assigning each risk factor based on the logistic regression coefficient: APACHE II score (10–15 score, 1 point; >15 score, 4 points); pneumonia (2 points), abdominal surgery (2 points), hypoproteinemia (2 points), and chronic renal insufficiency (4 points). Internal validation by 1,000 bootstrapping sample showed relatively high discriminative ability of the scoring system (C-index = 0.756, 95% confidence interval: 0.753–0.758).

Conclusions: The predictive scoring system based on APACHE II score, pneumonia, abdominal surgery, hypoproteinemia, and chronic renal insufficiency can help predict the risk of in-hospital death in patients with IAI.

Advances in the pharmacological management of bacterial peritonitis

Introduction: Bacterial peritonitis is an infection with high mortality if not treated immediately. In the absence of an intraabdominal source of infection, bacterial peritonitis may arise in patients with liver cirrhosis, in patients on peritoneal dialysis (PD) for end-stage renal disease or in patients with tuberculosis. In patients with cirrhosis, bacterial peritonitis may trigger acute on chronic liver failure with substantial mortality despite optimal treatment. In patients on PD, peritonitis may make continuation of PD impossible, necessitating the switch to hemodialysis.Areas covered: Recovery from peritonitis and prevention of complications depend on timely pharmacological management. Challenges are the broad microbiological spectrum with growing rates of antimicrobial resistance, the underlying chronic liver or kidney failure and high rates of relapse. The authors provide a review of predisposing conditions, diagnosis, and prevention of bacterial peritonitis with a particular focus on the pharmacological management.Expert opinion: Diagnosis of the type of bacterial peritonitis is essential to pharmacological management. In patients with spontaneous bacterial peritonitis, broad-spectrum antibiotics should be given intravenously in conjunction with albumin. In patients on PD, antibiotic therapy should be preferably applied intraperitoneally with empirical coverage of gram-positive and gram-negative bacteria. Secondary peritonitis usually requires surgical or interventional treatment.

Diagnosis and Management of Intraabdominal Infection: Guidelines by the Chinese Society of Surgical Infection and Intensive Care and the Chinese College of Gastrointestinal Fistula Surgeons

The Chinese guidelines for IAI presented here were developed by a panel that included experts from the fields of surgery, critical care, microbiology, infection control, pharmacology, and evidence-based medicine. All questions were structured in population, intervention, comparison, and outcomes format, and evidence profiles were generated. Recommendations were generated following the principles of the Grading of Recommendations Assessment, Development, and Evaluation system or Best Practice Statement (BPS), when applicable. The final guidelines include 45 graded recommendations and 17 BPSs, including the classification of disease severity, diagnosis, source control, antimicrobial therapy, microbiologic evaluation, nutritional therapy, other supportive therapies, diagnosis and management of specific IAIs, and recognition and management of source control failure. Recommendations on fluid resuscitation and organ support therapy could not be formulated and thus were not included. Accordingly, additional high-quality clinical studies should be performed in the future to address the clinicians' concerns.

Antibiotic-resistant microorganisms in patients with bloodstream infection of intraabdominal origin: risk factors and impact on mortality

BACKGROUND

Knowledge of resistance patterns is essential to choose empirical treatment. We aimed to determine the risk factors for antibiotic-resistant microorganisms (ARM) in intraabdominal infections (IAI) and their impact on mortality.

METHODS

Retrospective cohort study of patients with bacteremia from IAI origin in a single hospital between January 2006 and July 2017.

RESULTS

A total of 1485 episodes were recorded, including 381 (25.6%) due to ARM. Independent predictors of ARM were cirrhosis (OR 2; [95% CI 1.15-3.48]), immunosuppression (OR 1.49; 1.12-1.97), prior ceftazidime exposure (OR 3.7; 1.14-11.9), number of prior antibiotics (OR 2.33; 1.61-3.35 for 1 antibiotic), biliary manipulation (OR 1.53; 1.02-2.96), hospital-acquisition (OR 2.77; 1.89-4) and shock (OR 1.48; 1.07-2). Mortality rate of the whole cohort was 11.1%. Age (OR 1.03; 1.01-1.04), cirrhosis (OR 2.32; 1.07-4.38), urinary catheter (OR 1.99; 1.17-3.38), ultimately (OR 2.28; 1.47-3.51) or rapidly (OR 13.3; 7.12-24.9) fatal underlying disease, nosocomial infection (OR 2.76; 1.6-4.75), peritonitis (OR 1.95, 1.1-3.45), absence of fever (OR 2.17; 1.25-3.77), shock (OR 5.96; 3.89-9.13), and an ARM in non-biliary infections (OR 2.14; 1.19-3.83) were independent predictors of 30-day mortality. Source control (OR 0.24; 0.13-0.44) and 2015-2017 period (OR 0.29; 0.14-0.6) were protective.

CONCLUSION

Biliary manipulation and septic shock are predictors of ARM. The presence of an ARM from a non-biliary focus is a poor-prognosis indicator. Source control continues to be of paramount importance.

Antibiotic Resistance Patterns of Enterobacteriaceae Isolated from Patients with Healthcare-Associated Infections

BACKGROUND

There have been recent proposals to categorize healthcare-associated infections (HCAIs) separately from community-acquired infections (CAIs). The aim of this study was to compare the antibiotic resistance of pathogens causing CAIs, HCAIs, and hospital-acquired infections (HAIs) in Korea, and to investigate the need for different empirical antibiotics therapy for CAIs and HCAIs.

MATERIALS AND METHODS

This prospective study was conducted in a university hospital between March and December 2019. Inpatients who underwent a bacterial culture within 2 days of hospitalization, with a Enterobacteriaceae strain identified at the infection site and available antibiotic susceptibility results, were included in the analysis. Infections were classified as CAIs, HCAIs or HAIs, depending on the source.

RESULTS

Of the 146 patients included in the analysis, the prevalence of fluoroquinolone-resistant Enterobacteriaceae was 18.8%, 38.5%, and 55.0%; the prevalence of pathogens showing third-generation cephalosporins resistance was 8.3%, 50.0%, and 60.0%; and the prevalence of pathogens showing piperacillin-tazobactam resistance was 8.3%, 7.7%, 15.0% in the CAIs, HCAIs, and HAIs groups, respectively. The prevalence of extended-spectrum beta-lactamase-positive pathogens was 6.3%, 47.3%, and 55.0% in the CAIs, HCAIs, and HAIs group, respectively, with no significant difference between the HCAIs and HAIs groups. Resistance patterns of the HCAIs group more closely resembled those of the HAIs group than those of the CAIs group.

CONCLUSION

The pathogens isolated from patients with HCAIs showed resistance patterns that were more similar to those of patients with HAIs than those with CAIs. Thus, CAIs and HCAIs should be distinguished from each other when selecting antibiotic agents.

Systematic Review and Meta-Analysis of the Efficacy of Appropriate Empiric Anti-Enterococcal Therapy for Intra-Abdominal Infection

Background: Delayed treatment of seriously infected patients results in increased mortality. However, antimicrobial therapy for the initial 24 to 48 hours is mostly empirically provided, without evidence regarding the causative pathogen. Whether empiric anti-enterococcal therapy should be administered to treat intra-abdominal infection (IAI) before obtaining culture results remains unknown. We performed a meta-analysis to explore the effects of empiric enterococci covered antibiotic therapy in IAI and the risk factors for enterococcal infection in IAI. Methods: We searched multiple databases systematically and included 23 randomized controlled trials (RCTs) and 13 observational studies. The quality of included studies was assessed, and the reporting bias was evaluated. Meta-analysis was performed using random effects or fixed effects models according to the heterogeneity. The risk ratio (RR), odds ratio (OR), and 95% confidence interval (CI) were calculated. Results: Enterococci-covered antibiotic regimens provided no improvement in treatment success compared with control regimens (RR, 0.99; 95% CI, 0.97-1.00; p = 0.15), with similar mortality and adverse effects in both arms. Basic characteristic analysis revealed that most of the enrolled patients with IAI in RCTs were young, lower risk community-acquired intra-abdominal infection (CA-IAI) patients with a relatively low APACHE II score. Interestingly, risk factor screening revealed that malignancy, corticosteroid use, operation, any antibiotic treatment, admission to intensive care unit (ICU), and indwelling urinary catheter could predispose the patients with IAI to a substantially higher risk of enterococcal infection. "Hospital acquired" itself was a risk factor (OR, 2.81; 95% CI, 2.34-3.39; p < 0.001). Conclusion: It is unnecessary to use additional agents empirically to specifically provide anti-enterococcal coverage for the management of CA-IAI in lower risk patients without evidence of causative pathogen, and risk factors can increase the risk of enterococcal infection. Thus, there is a rationale for providing empiric anti-enterococcal coverage for severely ill patients with CA-IAI with high risk factors and patients with hospital-acquired intra-abdominal infection (HA-IAI).

A proposal for a comprehensive approach to infections across the surgical pathway

Despite evidence supporting the effectiveness of best practices in infection prevention and management, many healthcare workers fail to implement them and evidence-based practices tend to be underused in routine practice. Prevention and management of infections across the surgical pathway should always focus on collaboration among all healthcare workers sharing knowledge of best practices. To clarify key issues in the prevention and management of infections across the surgical pathway, a multidisciplinary task force of experts convened in Ancona, Italy, on May 31, 2019, for a national meeting. This document represents the executive summary of the final statements approved by the expert panel.

Evaluation of Amikacin Pharmacokinetics in Critically Ill Patients with Intra-abdominal Sepsis

Purpose: Although the current widespread use of amikacin is in intra-abdominal sepsis treatment, its pharmacokinetic changes in the present setting are not yet well known. This study was aimed to evaluate the amikacin pharmacokinetic profile in critically ill patients with intraabdominal sepsis compared to pneumosepsis.

Methods: Adult septic patients received amikacin therapy were studied. Patients with intraabdominal sepsis were enrolled in group 1 (n=16), and patients with pneumosepsis were enrolled in group 2 (n=13). The amikacin serum concentrations were evaluated in the first, second, fourth and sixth hours after initiating 30-minute infusion. The pharmacokinetic parameters were calculated for each patient.

Results: There was no significant difference in the volume of distribution between the two groups (0.33±0.08 vs. 0.28±0.10 L/kg, P=0.193). The amikacin clearance was significantly lower in group 1 compared to group 2 (58.5±21.7 vs. 83.9±37.0 mL/min, P=0.029). There was no significant correlation between amikacin clearance and creatinine clearance estimated by Cockcroft-Gault formula in all patients (P=0.206). The half-life was significantly longer in group 1 compared to group 2 (5.3±2.8 vs. 3.4±3.2 hours, P=0.015).

Conclusion: Pathophysiologic changes following intra-abdominal sepsis can affect amikacin pharmacokinetics behavior. The clearance and half-life may change, but the alteration of the volume of distribution is not significantly different in comparison with pneumosepsis. Further studies are required to evaluate the pharmacokinetic variables of amikacin in critically ill patients with intra-abdominal sepsis.

Critically ill patients with community-onset intraabdominal infections: Influence of healthcare exposure on resistance rates and mortality

The concept of healthcare-associated infections (as opposed to hospital-acquired infections) in intraabdominal infections (IAIs) is scarcely supported by data in the literature. The aim of the present study was to analyse community-onset IAIs (non-postoperative/non-nosocomial) in patients admitted to intensive care units (ICUs), to investigate differences in resistance patterns linked to healthcare exposure and mortality-associated factors. A one-year prospective observational study (17 Spanish ICUs) was performed distributing cases as healthcare-associated infections (HCAI), community-acquired infections (CAI) and immunocompromised patients (ICP). Bacteria producing extended-spectrum β-lactamases (ESBL) and/or carbapenemase (CPE), high-level aminoglycoside- and/or methicillin- and/or vancomycin- resistance were considered antimicrobial resistant (AMR). Mortality-associated factors were identified by regression multivariate analysis. Of 345 patients included (18.8% HCAI, 6.1% ICP, 75.1% CAI), 51.6% presented generalized peritonitis; 32.5% were >75 years (55.4% among HCAI). Overall, 11.0% cases presented AMR (7.0% ESBL- and/or CPE), being significantly higher in HCAI (35.4%) vs. CAI (5.8%) (p<0.001) vs. ICP (0%) (p = 0.003). Overall 30-day mortality was 14.5%: 23.1% for HCAI and 11.6% for CAI (p = 0.016). Mortality (R2 = 0.262, p = 0.021) was positively associated with age >75 years (OR = 6.67, 95%CI = 2.56-17.36,p<0.001), Candida isolation (OR = 3.05, 95%CI = 1.18-7.87,p = 0.022), and SAPS II (per-point, OR = 1.08, 95%CI = 1.05-1.11, p<0.001) and negatively with biliary infections (OR = 0.06, 95%CI = 0.01-0.48,p = 0.008). In this study, the antimicrobial susceptibility pattern of bacteria isolated from patients with healthcare contact was shifted to resistance, suggesting the need for consideration of the healthcare category (not including hospital-acquired infections) for severe IAIs. 30-day mortality was positively related with age >75 years, severity and Candida isolation but not with AMR.

Nationwide observational study of mortality from complicated intra-abdominal infections and the role of bacterial cultures

BACKGROUND

The benefit of taking intra-abdominal cultures during source control procedures in patients with complicated intra-abdominal infection (CIAI) is unknown. The aim of this study was to evaluate whether intra-abdominal cultures reduce the mortality rate of CIAI.

METHODS

The Japanese Diagnosis Procedure Combination database was used to identify adult patients with CIAI who had undergone source control procedures on the first day of admission to hospital between April 2014 and March 2016. In-hospital mortality was compared between patients who did and those who did not have intra-abdominal cultures taken. A generalized linear mixed-effect logistic regression model and a random intercept per hospital were used to adjust for baseline confounders and institutional differences. Subgroup analyses were also performed according to disease cause, site of onset and severity of CIAI.

RESULTS

Intra-abdominal cultures were taken from 16 303 of 41 495 included patients. Multivariable logistic regression analysis showed that patients with intra-abdominal cultures had a significantly lower mortality than those without (odds ratio 0·85, 95 per cent c.i. 0·77 to 0·95). Subgroup analyses revealed statistically significant differences in mortality between patients with and without cultures among those with lower intestinal perforation, biliary tract infection/perforation, healthcare-associated CIAI and high-risk community-acquired CIAI.

CONCLUSIONS

Intra-abdominal cultures obtained during source control procedures may reduce in-hospital mortality, especially in patients with lower intestinal perforation, biliary tract infection/perforation, or healthcare-associated or high-risk community-acquired CIAI.

Colorectal Surgical Site Infections and Their Causative Pathogens: Differences between Left- and Right-Side Resections

BACKGROUND

Surgical site infections (SSIs), after colorectal resection, pose a significant burden. Recognition of the spectrum of potentially involved pathogens is crucial for determining correct antibiotic prophylaxis. This study aimed to determine whether the distribution of SSI-associated pathogens depends on the location of the colorectal resection.

METHODS

We retrospectively categorized 2713 consecutive colon resections as left- or right-side operations, identified patients having concurrent peritonitis or development of postoperative SSIs and peritonitis, and assigned all subcutaneously and intra-abdominally isolated pathogens according to the location of the resection.

RESULTS

Gram-positive cocci (especially enterococci) and gram-negative bacilli (especially Pseudomonas aeruginosa) were isolated more frequently from patients in whom SSIs developed after left-side resections than after right-side resections (52.5% vs. 32.6%, p < 0.01 and 15.9% vs. 6.7%, p < 0.01, respectively); enterococci were the causative organisms in a large percentage of SSIs (46.3%). Moreover, intra-abdominal P. aeruginosa and Candida spp. were isolated more frequently during left-side resections than during right-side operations in patients with peritonitis (15.8% vs. 6.3%, p = 0.02 and 14.3% vs. 5.3%, p = 0.02, respectively).

CONCLUSIONS

Our results indicate that differences exist in the distribution of pathogens after left- or right-side colorectal resections. Our data further suggest that gram-positive cocci play an important role in SSIs occurring after colorectal resections; therefore, antibiotic prophylaxis should emphasize their coverage. Further, enterococcal coverage may be especially advantageous during left-side resections.

Secondary peritonitis: principles of diagnosis and intervention

Secondary peritonitis accounts for 1% of urgent or emergent hospital admissions and is the second leading cause of sepsis in patients in intensive care units globally. Overall mortality is 6%, but mortality rises to 35% in patients who develop severe sepsis. Despite the dramatic growth in the availability and use of imaging and laboratory tests, the rapid diagnosis and early management of peritonitis remains a challenge for physicians in emergency medicine, surgery, and critical care. In this article, we review the pathophysiology of peritonitis and its potential progression to sepsis, discuss the utility and limitations of the physical examination and laboratory and radiographic tests, and present a paradigm for the management of secondary peritonitis.

Microbial Spectrum of Intra-Abdominal Abscesses in Perforating Crohn's Disease: Results from a Prospective German Registry

BACKGROUND

Intra-abdominal abscesses [IAAs] are common life-threatening complications in patients with Crohn's disease [CD]. In addition to interventional drainage and surgical therapy, empirical antibiotic therapy represents a cornerstone of treatment, but contemporary data on microbial spectra and antimicrobial resistance are scarce.

METHODS

We recruited 105 patients with CD and IAAs from nine German centres for a prospective registry in order to characterize the microbiological spectrum, resistance profiles, antibiotic therapy and outcome.

RESULTS

In 92 of 105 patients, microbial investigations of abscess material revealed pathogenic microorganisms. A total of 174 pathogens were isolated, with a median of 2 pathogens per culture [range: 1-6]. Most frequently isolated pathogens were E. coli [45 patients], Streptococcus spp. [28 patients], Enterococci [27 patients], Candida [13 patients] and anaerobes [12 patients]. Resistance to third-generation cephalosporins, penicillins with beta-lactamase inhibitors and quinolones were observed in 51, 36 and 35 patients, respectively. Seven patients had multiple-drug-resistant bacteria. Thirty patients received inadequate empirical treatment, and this was more frequent in patients receiving steroids or immunosuppression [37%] than in patients without immunosuppression [10%: p = 0.001] and was associated with a longer hospital stay [21 days vs 13 days, p = 0.003].

CONCLUSION

Based on antimicrobial resistance profiles, we herein report a high rate of inadequate empirical first-line therapy for IAAs in CD, especially in patients receiving immunosuppression, and this is associated with prolonged hospitalization.

Antimicrobial susceptibility of common pathogens isolated from postoperative intra-abdominal infections in Japan

The principle of empirical therapy for patients with intra-abdominal infections (IAI) should include antibiotics with activity against Enterobacteriaceae and Bacteroides fragilis group species. Coverage of Pseudomonas aeruginosa, Enterobacter cloacae, and Enterococcus faecalis is also recommended for hospital-associated IAI. A nationwide survey was conducted to investigate the antimicrobial susceptibility of pathogens isolated from postoperative IAI. All 504 isolates were collected at 26 institutions and referred to a central laboratory for susceptibility testing. Lower susceptibility rates to ciprofloxacin and cefepime were demonstrated in Escherichia coli. Among E. coli, 24.1% of strains produced extended-spectrum β-lactamase (ESBL). Carbapenems, piperacillin/tazobactam, cephamycins/oxacephem, aminoglycosides, and tigecycline had high activity against E. coli, including ESBL-producing isolates. Among E. cloacae, low susceptibility rates to ceftazidime were demonstrated, whereas cefepime retained its activity. P. aeruginosa revealed high susceptibility rates to all antimicrobials tested except for imipenem. Among B. fragilis group species, low levels of susceptibility were observed for cefoxitin, moxifloxacin, and clindamycin, and high susceptibility rates were observed for piperacillin/tazobactam, meropenem, and metronidazole. Ampicillin, piperacillin, and glycopeptides had good activity against E. faecalis. Imipenem had the highest activity against E. faecalis among carbapenems. In conclusion, we suggested the empirical use of antimicrobials with the specific intent of covering the main organisms isolated from postoperative IAI. Piperacillin/tazobactam, meropenem, or doripenem, are appropriate in critically ill patients. Combination therapy of cefepime (aztreonam in patients with β-lactam allergy) plus metronidazole plus glycopeptides, imipenem/cilastatin or cephamycins/oxacephem plus ciprofloxacin plus metronidazole are potential therapeutic options.

Epidemiology and Risk Factors for Isolation of Multi-Drug-Resistant Organisms in Patients with Complicated Intra-Abdominal Infections

BACKGROUND

Patients with complicated intra-abdominal infections (cIAIs) caused by multi-drug-resistant organisms (MDROs) have been identified as being at increased risk for adverse outcomes. Prompt identification and stratification of these patients is essential in the clinical management, allowing the physician timely optimization of empiric antimicrobial therapy while awaiting results of intra-operative cultures to streamline antibiotic treatment.

METHODS

The study is a secondary analysis from two prospective multi-center color surveillance studies. It included all consecutively hospitalized adult patients undergoing surgical procedures, interventional drainage, or conservative treatment with cIAIs, with positive cultures performer on intra-operative samples of peritoneal fluid or purulent exudate/discrete abscesses. Patients with pancreatitis and primary peritonitis were excluded. A case-control approach has been used to evaluate the factors associated with the isolation of a MDRO in enrolled patients.

RESULTS

Among 1986 patients included in the study, a total of 3534 micro-organisms were isolated from intra-peritoneal fluid samples; in 46.5% of cultures, two or more pathogens were identified. The MDROs represented 9.8% of the total of isolated micro-organisms. The overall incidence rate of MDROs was 13.9%. The MDROs were more frequently isolated in patients with health-care-associated cIAIs (25.4%). Multi-nomial logistic regression analysis of risk factors demonstrated that statistically significant risk factors independently associated with the occurrence of MDROs were previous antimicrobial therapy administered within seven days before operation, presence of severe cardiovascular disease, white blood cell count <4000/mL or >12,000/mL, cIAI acquired in a healthcare setting, and inadequate source control.

CONCLUSIONS

The study showed that knowledge of five easily recognizable variables-assessable on hospital admission or as soon as the surgical intervention is concluded-might guide the surgeon to identify patients with cIAIs caused by MDROs, and therefore to choose the most adequate empiric antimicrobial therapy for them.

Longer-Duration Antimicrobial Therapy Does Not Prevent Treatment Failure in High-Risk Patients with Complicated Intra-Abdominal Infections

BACKGROUND

Recent studies have suggested the length of treatment of intra-abdominal infections (IAIs) can be shortened without detrimental effects on patient outcomes. However, data from high-risk patient populations are lacking. We hypothesized that patients at high risk for treatment failure will benefit from a longer course of antimicrobial therapy.

METHODS

Patients enrolled in the Study to Optimize Peritoneal Infection Therapy (STOP-IT) trial were evaluated retrospectively to identify risk factors associated with treatment failure, which was defined as the composite outcome of recurrent IAI, surgical site infection, or death. Variables were considered risk factors if there was a positive statistical association with treatment failure. Patients were then stratified according to the presence and number of these risk factors. Univariable analyses were performed using the Kruskal-Wallis, χ², and Fisher exact tests. Logistic regression controlling for risk factors and original randomization group, either a fixed four-day antimicrobial regimen (experimental) or a longer course based on clinical response (control), also was performed.

RESULTS

We identified corticosteroid use, Acute Physiology and Chronic Health Evaluation II score ≥5, hospital-acquired infection, or a colonic source of IAI as risk factors associated with treatment failure. Of the 517 patients enrolled, 263 (50.9%) had one or two risk factors and 16 (3.1%) had three or four risk factors. The rate of treatment failure rose as the number of risk factors increased. When controlling for randomization group, the presence and number of risk factors were independently associated with treatment failure, but the duration of antimicrobial therapy was not.

CONCLUSIONS

We were able to identify patients at high risk for treatment failure in the STOP-IT trial. Such patients did not benefit from a longer course of antibiotic administration. Further study is needed to determine the optimum duration of antimicrobial therapy in high-risk patients.

The Surgical Infection Society Revised Guidelines on the Management of Intra-Abdominal Infection

BACKGROUND

Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.

METHODS

Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.

RESULTS

This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.

SUMMARY

The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline.

Management of intra-abdominal infections: recommendations by the WSES 2016 consensus conference

This paper reports on the consensus conference on the management of intra-abdominal infections (IAIs) which was held on July 23, 2016, in Dublin, Ireland, as a part of the annual World Society of Emergency Surgery (WSES) meeting. This document covers all aspects of the management of IAIs. The Grading of Recommendations Assessment, Development and Evaluation recommendation is used, and this document represents the executive summary of the consensus conference findings.

Age and Its Impact on Outcomes with Intra-Abdominal Infection

BACKGROUND

Age has been shown to play a significant role in the etiology of complicated intra-abdominal infections (cIAIs), but the correlation between age and outcomes after therapy was not investigated in the Study to Optimize Peritoneal Infection Therapy (STOP-IT) trial.

PATIENTS AND METHODS

Data were obtained by post hoc analysis of the STOP-IT trial database. Patients were stratified by age <65 or ≥65 years. Primary outcomes were surgical site infection (SSI), recurrent IAI (recIAI), and death. Multivariable analysis was performed to identify independent predictors of outcomes.

RESULTS

There were 398 subjects <65 and 120 ≥ 65 years. Overall baseline characteristics of the two groups were similar. The site of infection was similar between groups except: Colon or rectum (48.3% vs. 29.9%, p = 0.0002) and biliary tree (16.7% vs. 9.1%, p = 0.02), which were more common in the older group, whereas small intestine (6.7% vs. 16.3%, p = 0.008) and appendix (4.2% vs.17.1%, p = 0.0004) were more common in the younger group. Among the primary outcomes, only death was significantly different between the age groups and was more prevalent in the ≥65 years group (4 [3.3%] vs. 1 [0.3%], p = 0.01). Surgical site infection (9.2% vs. 7.3%, p = 0.50), recIAI (15.8% vs. 14.4%, p = 0.69), and a composite outcome (26.7% vs. 20.4%, p = 0.14) were statistically similar between the age groups, and this remained true when controlling for other co-variables. Multivariable analyses did not reveal age as an independent predictor of the composite or individual outcomes.

CONCLUSION

Patients with a more advanced age demonstrated variable sources of infection relative to the younger cohort, yet received similar treatments. Patient age was not an independent predictor of the undesired cIAI outcomes. These findings suggest that advanced age itself does not play a significant role in predicting these adverse outcomes for cIAIs and does not necessitate an altered treatment tactic.

Intra-abdominal Infections: The Role of Anaerobes, Enterococci, Fungi, and Multidrug-Resistant Organisms

BACKGROUND

Intra-abdominal infections (IAI) constitute a common reason for hospitalization. However, there is lack of standardization in empiric management of (1) anaerobes, (2) enterococci, (3) fungi, and (4) multidrug-resistant organisms (MDRO). The recommendation is to institute empiric coverage for some of these organisms in "high-risk community-acquired" or in "healthcare-associated" infections (HCAI), but exact definitions are not provided.

METHODS

Epidemiological study of IAI was conducted at Assaf Harofeh Medical Center (May-November 2013). Logistic and Cox regressions were used to analyze predictors and outcomes of IAI, respectively. The performances of established HCAI definitions to predict MDRO-IAI upon admission were calculated by receiver operating characteristic (ROC) curve analyses.

RESULTS

After reviewing 8219 discharge notes, 253 consecutive patients were enrolled (43 [17%] children). There were 116 patients with appendicitis, 93 biliary infections, and 17 with diverticulitis. Cultures were obtained from 88 patients (35%), and 44 of them (50%) yielded a microbiologically confirmed IAI: 9% fungal, 11% enterococcal, 25% anaerobic, and 34% MDRO. Eighty percent of MDRO-IAIs were present upon admission, but the area under the ROC curve of predicting MDRO-IAI upon admission by the commonly used HCAI definitions were low (0.73 and 0.69). Independent predictors for MDRO-IAI were advanced age and active malignancy.

CONCLUSIONS

Multidrug-resistant organism-IAIs are common, and empiric broad-spectrum coverage is important among elderly patients with active malignancy, even if the infection onset was outside the hospital setting, regardless of current HCAI definitions. Outcomes analyses suggest that empiric regimens should routinely contain antianaerobes (except for biliary IAI); however, empiric antienterococcal or antifungals regimens are seldom needed.

Zinc Pyrithione Improves the Antibacterial Activity of Silver Sulfadiazine Ointment

Topical antimicrobial ointments ostensibly mitigate bacterial wound disease and reliance on systemic antibiotics. Yet studies have called into question the therapeutic benefits of several traditional topical antibacterials, accentuating the need for improved next-generation antimicrobial ointments. Yet the development of such agents consisting of a new chemical entity is a time-consuming and expensive proposition. Considering that drug combinations are a mainstay therapeutic strategy for the treatment of other therapeutic indications, one alternative approach is to improve the performance of conventional antimicrobial ointments by the addition of a well-characterized and FDA-approved agent. Here we report data that indicate that the antimicrobial properties of silver sulfadiazine ointments can be significantly improved by the addition of the antifungal zinc pyrithione, suggesting that such combinations may provide an improved therapeutic option for the topical treatment of wound infections.

Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus are commonly associated with biofilm-associated wound infections that are recalcitrant to conventional antibiotics. As an initial means to identify agents that may have a greater propensity to improve clearance of wound-associated bacterial pathogens, we screened a Food and Drug Administration-approved drug library for members that display bactericidal activity toward 72-h-established P. aeruginosa biofilms using an adenylate kinase reporter assay for bacterial cell death. A total of 34 compounds displayed antibiofilm activity. Among these, zinc pyrithione was also shown to reduce levels of A. baumannii and S. aureus biofilm-associated bacteria and exhibited an additive effect in combination with silver sulfadiazine, a leading topical therapeutic for wound site infections. The improved antimicrobial activity of zinc pyrithione and silver sulfadiazine was maintained in an ointment formulation and led to improved clearance of P. aeruginosa, A. baumannii, and S. aureus in a murine model of wound infection. Taken together, these results suggest that topical zinc pyrithione and silver sulfadiazine combination formulations may mitigate wound-associated bacterial infections and disease progression.

IMPORTANCE Topical antimicrobial ointments ostensibly mitigate bacterial wound disease and reliance on systemic antibiotics. Yet studies have called into question the therapeutic benefits of several traditional topical antibacterials, accentuating the need for improved next-generation antimicrobial ointments. Yet the development of such agents consisting of a new chemical entity is a time-consuming and expensive proposition. Considering that drug combinations are a mainstay therapeutic strategy for the treatment of other therapeutic indications, one alternative approach is to improve the performance of conventional antimicrobial ointments by the addition of a well-characterized and FDA-approved agent. Here we report data that indicate that the antimicrobial properties of silver sulfadiazine ointments can be significantly improved by the addition of the antifungal zinc pyrithione, suggesting that such combinations may provide an improved therapeutic option for the topical treatment of wound infections.

Inclusion of Vancomycin as Part of Broad-Spectrum Coverage Does Not Improve Outcomes in Patients with Intra-Abdominal Infections: A Post Hoc Analysis

BACKGROUND

Management of complicated intra-abdominal infections (cIAIs) includes broad-spectrum antimicrobial coverage and commonly includes vancomycin for the empiric coverage of methicillin-resistant Staphylococcus aureus (MRSA). Ideally, culture-guided de-escalation follows to promote robust antimicrobial stewardship. This study assessed the impact and necessity of vancomycin in cIAI treatment regimens.

PATIENTS AND METHODS

A post hoc analysis of the Study to Optimize Peritoneal Infection Therapy (STOP-IT) trial was performed. Patients receiving piperacillin-tazobactam (P/T) and/or a carbapenem were included with categorization based on use of vancomycin. Univariate and multivariable analyses evaluated effects of including vancomycin on individual and the composite of undesirable outcomes (recurrent IAI, surgical site infection [SSI], or death).

RESULTS

The study cohort included 344 patients with 110 (32%) patients receiving vancomycin. Isolation of MRSA occurred in only eight (2.3%) patients. Vancomycin use was associated with a similar composite outcome, 29.1%, vs. no vancomycin, 22.2% (p = 0.17). Patients receiving vancomycin had (mean [standard deviation]) higher Acute Physiology and Chronic Health Evaluation II scores (13.1 [6.6] vs. 9.4 [5.7], p < 0.0001), extended length of stay (12.6 [10.2] vs. 8.6 [8.0] d, p < 0.001), and prolonged antibiotic courses (9.1 [8.0] vs. 7.1 [4.9] d, p = 0.02). After risk adjustment in a multivariate model, no significant difference existed for the measured outcomes.

CONCLUSIONS

This post hoc analysis reveals that addition of vancomycin occurred in nearly one third of patients and more often in sicker patients. Despite this selection bias, no appreciable differences in undesired outcomes were demonstrated, suggesting limited utility for adding vancomycin to cIAI treatment regimens.

Therapeutic management of peritonitis: a comprehensive guide for intensivists

PURPOSE

The management of peritonitis in critically ill patients is becoming increasingly complex due to their changing characteristics and the growing prevalence of multidrug-resistant (MDR) bacteria.

METHODS

A multidisciplinary panel summarizes the latest advances in the therapeutic management of these critically ill patients.

RESULTS

Appendicitis, cholecystitis and bowel perforation represent the majority of all community-acquired infections, while most cases of healthcare-associated infections occur following suture leaks and/or bowel perforation. The micro-organisms involved include a spectrum of Gram-positive and Gram-negative bacteria, as well as anaerobes and fungi. Healthcare-associated infections are associated with an increased likelihood of MDR pathogens. The key elements for success are early and optimal source control and adequate surgery and appropriate antibiotic therapy. Drainage, debridement, abdominal cleansing, irrigation, and control of the source of contamination are the major steps to ensure source control. In life-threatening situations, a "damage control" approach is the safest way to gain time and achieve stability. The initial empirical antiinfective therapy should be prescribed rapidly and must target all of the micro-organisms likely to be involved, including MDR bacteria and fungi, on the basis of the suspected risk factors. Dosage adjustment needs to be based on pharmacokinetic parameters. Supportive care includes pain management, optimization of ventilation, haemodynamic and fluid monitoring, improvement of renal function, nutrition and anticoagulation.

CONCLUSIONS

The majority of patients with peritonitis develop complications, including worsening of pre-existing organ dysfunction, surgical complications and healthcare-associated infections. The probability of postoperative complications must be taken into account in the decision-making process prior to surgery.

New drugs for the treatment of complicated intra-abdominal infections in the era of increasing antimicrobial resistance

The continuing increase in multidrug-resistant organisms (MDROs) worldwide has created new challenges in treating complicated intra-abdominal infections (cIAIs). A number of novel antimicrobial agents have been developed against resistant pathogens. To target extended-spectrum β-lactamase (ESBL)-producing pathogens, novel β-lactam antibiotics, such as ceftolozane/tazobactam, ceftazidime/avibactam, aztreonam/avibactam, imipenem/relebactam and S-649266, are antimicrobial alternatives for cIAIs. Two new drugs, eravacycline and plazomicin, have activity against Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae, carbapenem-resistant Acinetobacter baumannii and ESBL-producers. New lipoglycopeptides and oxazolidinones provide feasible options against resistant Gram-positive pathogens. These novel antimicrobials may play a role in improving the clinical outcomes of cIAIs caused by MDROs.

Basis for selecting optimum antibiotic regimens for secondary peritonitis

Adequate management of severely ill patients with secondary peritonitis requires supportive therapy of organ dysfunction, source control of infection and antimicrobial therapy. Since secondary peritonitis is polymicrobial, appropriate empiric therapy requires combination therapy in order to achieve the needed coverage for both common and more unusual organisms. This article reviews etiological agents, resistance mechanisms and their prevalence, how and when to cover them and guidelines for treatment in the literature. Local surveillances are the basis for the selection of compounds in antibiotic regimens, which should be further adapted to the increasing number of patients with risk factors for resistance (clinical setting, comorbidities, previous antibiotic treatments, previous colonization, severity…). Inadequate antimicrobial regimens are strongly associated with unfavorable outcomes. Awareness of resistance epidemiology and of clinical consequences of inadequate therapy against resistant bacteria is crucial for clinicians treating secondary peritonitis, with delicate balance between optimization of empirical therapy (improving outcomes) and antimicrobial overuse (increasing resistance emergence).

Empiric therapy for hospital-acquired, Gram-negative complicated intra-abdominal infection and complicated urinary tract infections: a systematic literature review of current and emerging treatment options

BACKGROUND

Empiric therapy for healthcare-associated infections remains challenging, especially with the continued development of Gram-negative organisms producing extended-spectrum β-lactamases (ESBLs) and the threat of multi-drug-resistant organisms. Current treatment options for resistant Gram-negative infections include carbapenems, tigecycline, piperacillin-tazobactam, cefepime, ceftazidime, and two recently approved therapies, ceftolozane-tazobactam and ceftazidime-avibactam.

METHODS

This systematic literature review surveys the published clinical trial evidence available since 2000 in support of both current and emerging treatment options in the settings of complicated intra-abdominal infection (cIAI) and complicated urinary tract infection (cUTI). When available, clinical cure rates for patients with infections from ESBL-producing strains are provided, as is information about efficacy against Pseudomonas aeruginosa.

RESULTS

Clinical trial evidence to guide selection of empiric antibiotic therapy in patients with complicated, hospital-acquired, Gram-negative IAIs and UTIs is limited. Though most of the clinical trials explored in this overview enrolled patients with complicated infections, often patients with severe infections and multiple comorbidities were excluded.

CONCLUSIONS

Practitioners in the clinical setting who are treating patients with complicated, hospital-acquired, Gram-negative IAIs and UTIs need to consider the possibility of polymicrobial infections, antibiotic-resistant organisms, and/or severely ill patients with multiple comorbidities. There is a severe shortage of evidence-based research to guide the selection of empiric antibiotic therapy for many patients in this setting. New therapies recently approved or in late-stage development promise to expand the number of options available for empiric therapy of these hospital-acquired, Gram-negative infections.

Can Nasal Methicillin-Resistant Staphylococcus aureus Screening Be Used to Avoid Empiric Vancomycin Use in Intra-Abdominal Infection?

BACKGROUND

Vancomycin is used widely as empiric therapy for gram-positive organisms in patients with an intra-abdominal infection (IAI), even in those with no history of methicillin-resistant Staphylococcus aureus (MRSA) infection or colonization. Potential adverse effects of vancomycin include nephrotoxicity, increased cost, and bacterial resistance. We hypothesized that MRSA nasal screening could be used to predict patients with a MRSA IAI and used to avoid unnecessary empiric vancomycin use.

METHODS

A surgical infections database collected prospectively from a single institution was reviewed for all IAIs between January 1, 2000-December 31, 2011. Patients with and without MRSA obtained from abdominal cultures as either a monomicrobial or polymicrobial isolate were compared by univariate analysis. A multivariable logistic regression was performed to identify independent predictors of MRSA IAI.

RESULTS

Of 2,591 patients with an IAI, 240 patients had a nasal MRSA screen within 30 d prior to infection and abdominal culture data, with an incidence of 23% for MRSA IAI. Patients with MRSA IAI (n=45) had more healthcare associated infections, lower white blood cell counts and greater rates of positive nasal MRSA screenings compared with those with non-MRSA IAI. By multivariable analysis (C statistic=0.908), the strongest independent predictor of an MRSA IAI was a positive MRSA screen (odds ratio [OR] 40.9, confidence interval [CI] 14.2-118.1). The positive predictive value for a MRSA screen was 53% whereas the negative predictive value of a MRSA screen was 97%.

CONCLUSION

A negative MRSA nasal screen indicates with near certainty the absence of MRSA as part of an IAI. In the setting of a recent screen, empiric vancomycin can be withheld. Further, rapid MRSA nasal screening could be used to forego or to discontinue vancomycin therapy rapidly in the setting of IAI. This change in empiric antibiotic management of IAI may lead to decreased morbidity, reduction in cost, and a decrease in bacterial resistance.

Clinical characteristics of ceftriaxone plus metronidazole in complicated intra-abdominal infection

Purpose

Empirical antibiotics in complicated intra-abdominal infection (c-IAI), such as secondary peritonitis are a first step of treatment. Empirical antibiotic regimen is very diverse. Ceftriaxone plus metronidazole regimen (CMR) is one of the empirical antibiotic regimens used in treatment of c-IAI. However, although CMR is a widely used empirical antibiotic regimen, study regarding success, failure or efficacy of CMR has been poorly understood. This retrospective study is conducted to compare the clinical efficacy of this regimen in c-IAI according to clinical characteristics.

Methods

The subjects were patients in this hospital who were diagnosed as secondary peritonitis between 2009 and 2013. Retrospective analysis was performed based on the records made after surgery regarding clinical characteristics including albumin level, blood pressure, pulse rate, respiration rate, smoking, age, sex, body mass index, hemoglobin, coexisting disease, leukocytosis, and APACHE (acute physiology and chronic health evaluation) II score.

Results

A total of 114 patients were enrolled. In univariated analysis, the success and failure of CMR showed significant association with preoperative low albumin, old age, and preoperative tachycardia. In multivariated analysis, low albumin and preoperative tachycardia were significant.

Conclusion

It is thought that an additional antibiotic treatment plan is necessary in patients with low albumin and tachycardia when the empirical antibiotic regimen is CMR in c-IAI. Conduct of research through well-designed prospective randomized clinical study is also necessary in order to evaluate the appropriateness of CMR and decide on a proper empirical antibiotic regimen between many regimens in c-IAI based on our country.

Guidelines for management of intra-abdominal infections

Intra-abdominal infections are one of the most common gastrointestinal emergencies and a leading cause of septic shock. A consensus conference on the management of community-acquired peritonitis was published in 2000. A new consensus as well as new guidelines for less common situations such as peritonitis in paediatrics and healthcare-associated infections had become necessary. The objectives of these Clinical Practice Guidelines (CPGs) were therefore to define the medical and surgical management of community-acquired intra-abdominal infections, define the specificities of intra-abdominal infections in children and describe the management of healthcare-associated infections. The literature review was divided into six main themes: diagnostic approach, infection source control, microbiological data, paediatric specificities, medical treatment of peritonitis, and management of complications. The GRADE(®) methodology was applied to determine the level of evidence and the strength of recommendations. After summarising the work of the experts and application of the GRADE(®) method, 62 recommendations were formally defined by the organisation committee. Recommendations were then submitted to and amended by a review committee. After 2 rounds of Delphi scoring and various amendments, a strong agreement was obtained for 44 (100%) recommendations. The CPGs for peritonitis are therefore based on a consensus between the various disciplines involved in the management of these patients concerning a number of themes such as: diagnostic strategy and the place of imaging; time to management; the place of microbiological specimens; targets of empirical anti-infective therapy; duration of anti-infective therapy. The CPGs also specified the value and the place of certain practices such as: the place of laparoscopy; the indications for image-guided percutaneous drainage; indications for the treatment of enterococci and fungi. The CPGs also confirmed the futility of certain practices such as: the use of diagnostic biomarkers; systematic relaparotomies; prolonged anti-infective therapy, especially in children.

Evaluation of regional antibiograms to monitor antimicrobial resistance in Hampton Roads, Virginia

We studied recent antibiograms (2010 to 2011) from 12 hospitals in the Hampton Roads area, Virginia, that refer patients to a tertiary-care facility affiliated with Eastern Virginia Medical School. The data was compiled into a regional antibiogram, and sensitivity rates of common isolates from the tertiary-care facility (central) were compared to those of referring hospitals grouped by locale. Staphylococcus aureus was the most common Gram- positive and E. coli the most common Gram- negative organism grown from clinical samples in the area. Overall 53% of S.aureus isolates were resistant to oxacillin. There was a broad scatter of MIC (minimum inhibitory concentration) for vancomycin within the susceptibility range, and MIC of 4 μg/mL was reported in 2012. Penicillin resistance was seen in 50% and erythromycin resistance in 45% of Streptococcus pneumoniae. Vancomycin resistance was seen in 75% of Enterococcus faecium and 2% of Enterococcus faecalis respectively. Acinetobacter baumannii was the most resistant Gram negative organism in the data compiled. Among the Escherichia coli, 26%, 44% and 52%were resistant to Trimethoprim/Sulfamethoxazole ( SXT) ampicillin- sulbactam and ampicillin respectively. We found significant differences in methodology, interpretation and antibiotic panels used by area laboratories. Based on these findings, we are now prospectively following resistance patterns in the tertiary-care facility, sharing data, and creating a consistent approach to antimicrobial susceptibility testing in the region.

The Challenge of Antimicrobial Resistance in Managing Intra-Abdominal Infections

BACKGROUND

In recent years, there has been a worldwide increase in infections caused by microorganisms resistant to multiple antimicrobial agents.

METHODS

In the past few decades, an increased prevalence of infections caused by antibiotic-resistant pathogens, including Enterococcus spp., carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii, extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella spp., carbapenemase-producing Klebsiella pneumoniae, and resistant Candida spp., also has been observed among intra-abdominal infections (IAIs).

RESULTS

The increasing prevalence of multi-drug resistance is responsible for a substantial increase in morbidity and mortality rates associated with IAIs.

CONCLUSIONS

It is necessary for every surgeon treating IAIs to understand the underlying epidemiology and clinical consequences of antimicrobial resistance. Emergence of drug resistance, combined with the lack of new agents in the drug development pipeline, indicates that judicious antimicrobial management will be necessary to preserve the utility of the drugs available currently.

Clinical significance of surveillance culture in liver transplant recipients

BACKGROUND

Routine microbiologic surveillance is a method of infection control, but its clinical significance in transplant recipients is not known. We analyzed microbiologic data to evaluate the influence of cultured microorganisms between the point of surveillance and infectious episodes in liver transplant recipients.

METHODS

We performed surveillance culture for sputum and peritoneal fluid in liver transplant recipients from January 2009 to December 2011, at the time of transplantation (T1), 5 days (T2), and 10 days (T3) postoperatively.

RESULTS

Of the 179 recipients, 32.9% had a positive sputum culture result and 37.4% had a positive peritoneal culture result during surveillance. In the culture surveillance of sputum, 37 organisms were isolated from 35 recipients at T1, and the most common organism was Staphylococcus aureus (n = 13). At T2, 45 organisms were isolated from 39 recipients, including Klebsiella pneumoniae (n = 10), S aureus (n = 8), and Acinetobacter baumannii (n = 6). At T3, 18 organisms were isolated from 15 patients, including Stenotrophomonas maltophilia (n = 5) and K pneumonia (n = 4). In the peritoneal fluid, 11 organisms were isolated from 10 recipients at T1, including Pseudomonas aeruginosa (n = 2) and Enterococcus species (n = 2). At T2, 39 organisms were isolated from 36 recipients, including coagulase-negative Staphylococcus species (CNS; n = 8) and Enterococcus species (n = 7). At T3, 54 organisms were isolated from 51 recipients, including CNS (n = 17) and Candida species (n = 8). Among the 59 patients with positive culture results for sputum surveillance, 16.9% developed pneumonia caused by the same organisms. Among the 67 patients with positive peritoneal fluid culture, 16.4% developed an intra-abdominal infection caused by the same organisms cultured. The recipients with positive surveillance culture had a higher risk of pneumonia (20.3% [12/59] vs 1.6% [2/120]; P < .001) and intra-abdominal infection (31.3% [21/67] vs 18.7% [21/112]; P = .05).

CONCLUSIONS

Periodic microbiologic surveillance may be useful in the prediction of post-transplantation pneumonia and intra-abdominal infection and could offer a potential target for empirical antimicrobial therapy in cases of infection.

How to treat infections in a surgical intensive care unit

The management of infections in surgical intensive care unit patients poses specific challenges. Although the overall approach to the patient is no different from other patients, diagnosis is often problematic. As in other infections, multidrug resistance is increasingly described, and changes in pharmacokinetics may require different dosing strategies. Also the need for source control adds a level of complexity to the management of the patient. Whereas source control was a purely surgical issue before, percutaneous drainage has emerged as an important alternative. Appropriate timing of source control often remains difficult to determine, but in most severe infections source control should not be delayed. But also the need for a multidisciplinary approach can make the decision making difficult. New concepts such as dedicated source control teams may further assist in selecting the most appropriate treatment strategy and further improve outcome of surgical severe sepsis patients.

Impact of Surgical Infection Society/Infectious Disease Society of America-recommended antibiotics on postoperative intra-abdominal abscess with image-guided percutaneous abscess drainage following gastrointestinal surgery

PURPOSE

The aims of this study were to reveal how using the antibiotics recommended by the 2010 Surgical Infection Society (SIS) and Infectious Disease Society of America (IDSA) guidelines can affect the therapeutic outcomes.

METHODS

We reviewed the cases of 53 patients with a postoperative intra-abdominal abscess without anastomotic leakage after gastrointestinal surgery who underwent image-guided percutaneous abscess drainage (PAD) and concomitant antibiotic therapy. The type of antibiotic initially administered was determined based on the surgeon's judgment. A persistent abscess was defined as one or more PAD procedures resulting in complete resolution after 21 or more days. The recommended antibiotics were defined according to 2010 SIS/IDSA guidelines.

RESULTS

All 53 patients had complete resolution without the need for surgery. The results of a multivariable analysis revealed that a C-reactive protein level ≥12 mg/dL and non-recommended antibiotics were significant risk factors for a persistent abscess (P = 0.042 and 0.013, respectively). With regard to a fever lasting more than 48 h, there was a significant difference between the recommended (45.1%) and non-recommended (72.7 %) antibiotic groups (P = 0.046).

CONCLUSIONS

Using the recommended antibiotics may shorten the time to defervescence and reduce the risk of a persistent abscess in patients undergoing PAD for a postoperative abscess after gastrointestinal surgery.

Intra-abdominal Infections

Intra-abdominal infections are multifactorial, but all require prompt identification, diagnosis, and treatment. Resuscitation, early antibiotic administration, and source control are crucial. Antibiotic administration should initially be broad spectrum and target the most likely pathogens. When cultures are available, antibiotics should be narrowed and limited in duration. The method of source control depends on the anatomic site, site accessibility, and the patient's clinical condition. Patient-specific factors (advanced age and chronic medical conditions) as well as disease-specific factors (health care-associated infections and inability to obtain source control) combine to affect patient morbidity and mortality.

Bacterial species-specific hospital mortality rate for intra-abdominal infections

BACKGROUND

Intra-abdominal infections (IAIs) are a major cause of morbidity and death. We hypothesized that the involvement of specific organisms would predict death independently.

PATIENTS AND METHODS

All patients with IAIs treated at an academic tertiary-care facility over eight years (June 1999-June 2007) were included. The data collected were demographics, co-morbidities, source of infection, intra-abdominal culture results, type of infection (community-acquired vs. nosocomial), type of intervention (operative vs. percutaneous drainage), and outcome. The Charlson Comorbidity Index and multiple organ dysfunction score (MODS) were used in the analysis.

RESULTS

A total of 389 patients were admitted for 452 infection episodes (IEs) during the study period. None of the 129 patients with appendiceal-related infections died, and these patients were excluded from further analysis. Thus, 323 non-appendiceal IEs were evaluated. The overall mortality rate was 8.7%. The mean age of the patients was 54 y, and 50% of them were male. Intra-abdominal cultures were obtained from 303 IEs (93.8%). The most common cause of IAI was post-operative infection (44%). There were 49 distinct species isolated. The most common were Enterococcus (105), Escherichia coli (75), Streptococcus (62), Staphylococcus (51), and Bacteroides (46). Bivariable analysis revealed multiple risk factors associated with death. Logistic regression demonstrated that independent risk factors for death were age ≥65 years (odds ratio [OR] 3.92), cardiac event (OR=8.17), catheter-related blood stream infection (OR=6.16), and growth of Clostridium (OR=13.03). The growth of Streptococcus was predictive of survival. The C statistic was 0.89.

CONCLUSIONS

In addition to age and intrinsic patient factors, the presence of specific bacterial organisms independently predicts death in patients with non-appendiceal IAI.

Classification of healthcare-associated infection: a systematic review 10 years after the first proposal

BACKGROUND

Ten years after the first proposal, a consensus definition of healthcare-associated infection (HCAI) has not been reached, preventing the development of specific treatment recommendations. A systematic review of all definitions of HCAI used in clinical studies is made.

METHODS

The search strategy focused on an HCAI definition. MEDLINE, SCOPUS and ISI Web of Knowledge were searched for articles published from earliest achievable data until November 2012. Abstracts from scientific meetings were searched for relevant abstracts along with a manual search of references from reports, earlier reviews and retrieved studies.

RESULTS

The search retrieved 49,405 references: 15,311 were duplicates and 33,828 were excluded based on title and abstract. Of the remaining 266, 43 met the inclusion criteria. The definition more frequently used was the initial proposed in 2002--in infection present at hospital admission or within 48 hours of admission in patients that fulfilled any of the following criteria: received intravenous therapy at home, wound care or specialized nursing care in the previous 30 days; attended a hospital or hemodialysis clinic or received intravenous chemotherapy in the previous 30 days; were hospitalized in an acute care hospital for ≥2 days in the previous 90 days, resided in a nursing home or long-term care facility. Additional criteria founded in other studies were: immunosuppression, active or metastatic cancer, previous radiation therapy, transfer from another care facility, elderly or physically disabled persons who need healthcare, previous submission to invasive procedures, surgery performed in the last 180 days, family member with a multi-drug resistant microorganism and recent treatment with antibiotics.

CONCLUSIONS

Based on the evidence gathered we conclude that the definition initially proposed is widely accepted. In a future revision, recent invasive procedures, hospitalization in the last year or previous antibiotic treatment should be considered for inclusion in the definition. The role of immunosuppression in the definition of HCAI still requires ongoing discussion.

A procalcitonin-based algorithm to guide antibiotic therapy in secondary peritonitis following emergency surgery: a prospective study with propensity score matching analysis

Background

Procalcitonin (PCT)-based algorithms have been used to guide antibiotic therapy in several clinical settings. However, evidence supporting PCT-based algorithms for secondary peritonitis after emergency surgery is scanty. In this study, we aimed to investigate whether a PCT-based algorithm could safely reduce antibiotic exposure in this population.

Methods/Principal Findings

From April 2012 to March 2013, patients that had secondary peritonitis diagnosed at the emergency department and underwent emergency surgery were screened for eligibility. PCT levels were obtained pre-operatively, on post-operative days 1, 3, 5, and 7, and on subsequent days if needed. Antibiotics were discontinued if PCT was <1.0 ng/mL or decreased by 80% versus day 1, with resolution of clinical signs. Primary endpoints were time to discontinuation of intravenous antibiotics for the first episode and adverse events. Historical controls were retrieved for propensity score matching. After matching, 30 patients in the PCT group and 60 in the control were included for analysis. The median duration of antibiotic exposure in PCT group was 3.4 days (interquartile range [IQR] 2.2 days), while 6.1 days (IQR 3.2 days) in control (p < 0.001). The PCT algorithm significantly improves time to antibiotic discontinuation (p < 0.001, log-rank test). The rates of adverse events were comparable between 2 groups. Multivariate-adjusted extended Cox model demonstrated that the PCT-based algorithm was significantly associated with a 87% reduction in hazard of antibiotic exposure within 7 days (hazard ratio [HR] 0.13, 95% CI 0.07–0.21, p < 0.001), and a 68% reduction in hazard after 7 days (adjusted HR 0.32, 95% CI 0.11–0.99, p  =  0.047). Advanced age, coexisting pulmonary diseases, and higher severity of illness were significantly associated with longer durations of antibiotic use.

Conclusions/Significance

The PCT-based algorithm safely reduces antibiotic exposure in this study. Further randomized trials are needed to confirm our findings and incorporate cost-effectiveness analysis.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12612000601831